On Sunday 18 February 2007 10:28, Uri Even-Chen wrote: > On 2/18/07, Arieh Skliarouk <[EMAIL PROTECTED]> wrote: > > I see only-tables conversion as good first step. There is howto on > > access-mysql conversion: > > http://www.kitebird.com/articles/access-migrate.html > > There is a great feature we use with the tables stored in Microsoft > Access. I defined one-to-many connections between tables - at least > 50 connections. Access enforces these connections - you can't add a > record to the table with "many" if there is not a key in the table > with "one" connected to it. You also can't modify the key data on > both connected sides, and you can't delete connected records on the > "one" side of the connection. If I want to create an Access query, I > open the tables database and add tables, and the connections are added > automatically.
There could be a problem with that. With the cascading record updates plus deletes (which are dangerous mind u) and many to one restrictions. You see, IIRC all you have to do is link the tables from the access table list to the tables in mysql/postgresql. However, the cascading thingie might not work. i.e.: if u delete a record on one table it's foreign key is redirected and the record it was connected to is also deleted (and vice versa). If you use cascading thing, you should first try to see if it works on the server. Simple to do. The one to many connections can be enforced in any database (specifically postgresql which i know well) and also the cascading thing can be done in probably any database. The question is, will it work automatically without you doing anything but linking the tables. If you are undeterred by about 1hr-2hr additional work you can also do it in mysql/postgresql whatever. > > Are there table connections in MySQL? If not, I don't think we will > want to use MySQL. I can live without the automatic query feature > (although it's very convenient), but without connections the database > can get corrupted. Access prevents us from deleting records which are > connected to "many" records in other tables, and without the > connections they can be deleted. It can create all sorts of mess. > For example, if you have an employee with all sorts of data, and the > employee leaves the company. If you delete the employee, the data > will not be connected and will have an "employee ID" which is not > valid. The "employee ID" is just a number, you will not even know who > is the employee. Tomorrow you might add another employee and give him > the same number, and the data will be connected to him. For example, > he can be listed as the person who signed orders, and not the former > employee. The Access connections will not let you delete an employee > record if it has data connected to it. In this respect, I don't think > MySQL is compatible with Access. > > Uri. > > ================================================================= > To unsubscribe, send mail to [EMAIL PROTECTED] with > the word "unsubscribe" in the message body, e.g., run the command > echo unsubscribe | mail [EMAIL PROTECTED] -- Regards, Tzahi. -- Tzahi Fadida Blog: http://tzahi.blogsite.org | Home Site: http://tzahi.webhop.info WARNING TO SPAMMERS: see at http://members.lycos.co.uk/my2nis/spamwarning.html ================================================================To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
